package NC24_删除有序链表中重复的元素2;

import java.util.*;

class ListNode {
    int val;
    ListNode next = null;

    public ListNode(int val) {
        this.val = val;
        this.next = null;
    }
}
public class Solution {
    /**
     *
     * @param head ListNode类
     * @return ListNode类
     */
    public ListNode deleteDuplicates (ListNode head) {
        // write code here
        if (head == null || head.next == null){
            return head;
        }

        if (head.val != head.next.val){
            head.next = deleteDuplicates(head.next);
            return head;
        }else {
            int tmp = head.val;
            while (head.val == tmp){
                head = head.next;
                if (head == null){
                    return null;
                }
            }
            return deleteDuplicates(head);
        }
    }
}